A court in Kenya has ordered five Kenyans and a Tanzanian to be arrested for 30 days as police authorities probe their possible links to a recent terrorist attack on a university in the African country, which left nearly 150 people dead.

On Tuesday, the Nairobi court agreed to state lawyers’ request for the extended detention period, which usually would last 24 hours before the detainee has to appear in court.

Lawyers for the police said the five Kenyans have been placed under investigation to determine how they supplied weapons to al-Shabab militants, who carried out the April 2 assault on a university in Kenya’s northeastern town of Garissa.

The attack claimed the lives of 142 students, three police officers and three soldiers.

The Tanzanian and a Kenyan, who was a security guard at the campus, were arrested at the site. The others were also detained while trying to cross the border into Somalia.

Kenyan authorities have offered a $215,000 (200,000 euro) bounty for former Kenyan teacher and purported al-Shabab militant commander, Mohamed Mohamud, who is believed to have masterminded the Garissa attack.

On Monday, Kenyan military aircraft pounded two camps of al-Qaeda-linked al-Shabab militants in Somalia’s southern Gedo region.

The airborne raids came as Kenyan President Uhuru Kenyatta had pledged that he would retaliate “in the severest way possible” against al-Shabab militants for last week’s university massacre.

Last week, the al-Shabab militant group threatened “another bloodbath” and warned of a “long, gruesome war” unless Kenya withdraws its troops from Somalia.

The militants have carried out a string of revenge attacks in Kenya as well as neighboring Uganda over their participation in African Union Mission to Somalia (AMISOM) force.

In September 2013, the Westgate Mall in the Kenyan capital, Nairobi, was attacked and around 70 people died in a four-day standoff at the site. Al-Shabab militants claimed responsibility for the attack.

Somalia has been the scene of deadly clashes between government forces and al-Shabab militants since 2006.

The militants have been pushed out of the Somali capital, Mogadishu, and other major cities in the country by government forces and the AMISOM, which is largely made up of troops from Ethiopia, Uganda, Burundi, Djibouti, Sierra Leone and Kenya.

MP/MKA/SS